Polyorganosiloxane, which is a kind of silicone, means a polymer having a siloxane linkage substituted with organic groups as a backbone. As an example, it is produced by polycondensation of an aromatic diol such as bisphenol A and a carbonate precursor such as phosgene, is colorless and odorless, is slow to oxidize, is a hypoallergenic insulator that is stable even at room temperature, and is used as electrics, electronics, automobiles, machinery, medicines, cosmetics, lubricants, adhesives, gaskets, plastic artificial aids and the like. As a conventional technique, Korean Patent Publication No. 10-2002-0016922 (published on Mar. 6, 2002) discloses trimethylsilyl-terminated polyorganosiloxanes useful as materials for hydrogel contact lenses.
In addition, it has excellent impact strength, dimensional stability, thermal resistance and transparency, and is applied to a wide range of fields such as exterior materials of electrical and electronic products, automotive parts, construction materials, optical components, and the like. Recently, in order to apply these polycarbonate resins to more various fields, many attempts have been made to obtain desired physical properties by copolymerizing two or more aromatic diols having different structures from each other and introducing monomers having different structures in a main chain of the polycarbonate.
Especially, studies for introducing a polysiloxane structure in a main chain of the polycarbonate have been undergone, but most of these technologies have disadvantages in that production costs are high, and if chemical resistance or impact strength, particularly impact strength at low-temperature is increased, transparency and like are conversely lowered, and if the transparency is improved, the chemical resistance, impact resistance and the like are lowered.
Specifically, U.S. Pat. No. 5,932,677 discloses about using eugenol-polydimethylsiloxane to improve impact strength at low temperatures, and Japanese Patent Registration No. 3,195,848 suggests allylphenol-polydimethylsiloxane.
However, as the application field of the copolycarbonate is expanded, the required hardness of the copolycarbonate is gradually increased. Accordingly, there is a need to develop a copolycarbonate having a novel structure capable of improving the hardness while maintaining the intrinsic physical properties of the copolycarbonate.
In this regard, the present inventors have conducted intensive studies to develop a copolycarbonate having improved hardness and chemical resistance, and found that by introducing an alkylene or isosorbide in a polyorganosiloxane structure used as a monomer of a copolycarbonate as described below, it is possible to improve the hardness and chemical resistance simultaneously while maintaining the intrinsic physical properties of the copolycarbonate, thereby completing the present invention.